Binocular microscope.



Draftsman PATENTED SEPT. 15, 1903.

F- E- IVES. BINOCULAR MICRUSCOPB. APP-LIOATIOH TILED nov. a, 1902.

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3 .182. PATEN'I'ED-SBPT.15, 1903. P. E. IVES. BINOGULAR MICROSCOPE. APPLIOATIOF FILED NOV. 8, 1902. H0 MODEL.

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UNITED STATES Patented September 15, 1903.

PATENT OFFIC BIN'OCULAR MICROSCOPE.

SPECIFICATION forming part of Letters Patent No. 7 39,182, dated September 15, 1903. Application filed November 8,1902. Serial No. 130,541. (No model.)

- vention, and Figs. 2, 3, and 4 are views illustrating other embodiments of the invention or parts of the same..

Referring in the first instance to Fig. 1, which represents an ordinary compound microscope that has been'converted into a binocular microscope inaccordance with my invention, 1 represents the tube of the microscope, which has at the lower end a cap 2 with threaded opening, into which ordinarily screws the tube 3, carrying the objective lenses. Into this threaded opening in the cap 2 is now screwed a threaded tubular stem 4 upon a box or casing 5, which has a threaded opening for the reception of the tube 3 and is provided with a compound cemented prism 6 7 and a single prism 8, the latter being pivotally mounted within the box 5, so that the angle of its inclined reflecting face can be varied.

3 5 The compound cemented prism 6 7 has transparent silvering or platinizing on one of the inner cemented faces, s'othat a portion of the light-rays will be transmitted through said prism, and a portion will be laterally reflected 0 onto the reflecting-surface of the prism 8 and will thereby be deflected upwardly. at an angle dependent upon the angle of said reflectingsurface. 1

The tube I of the microscope has within it a telescopic tube 9, guided within a tube 10,

. which is carried by-a ring 11, "screwed into the threaded upper end of the tube 1, and within 1, the telescopic tube 9 is a sliding eyepiece 12,

- equipped with appropriate lenses. 5o Between the upper end of the tube 1 and the ring 11 is secured a laterally-projecting. plate or bar 13, which carries a clamp-screwlat, the latter having a stem which is adapted to a slot 15 in a plate or bar 16, said bar 16 carrying a tube 17, containing a sliding eyepiece 18, similar to that of the main tube of the microscope, this construction permitting adjustment of the two eyepieces toward and from each other to accord with the pupillary distance of the eyes of the observer or for ob- 6o taining stereoscopic or pseudoscopic effects, 7 as hereinafter explained.

The clamp-screw 14 serves to firmly secure the adjustable eyepiece in its desired position of adjustment, and the provision for varying the angle of the prism 8 permits ready adaptation of the latter to any required separation of the two eyepieces.

The prism 8 is extended in the direction of the axial lin'e'of the supplementary eyepiecef7o v 1 for the purpose of making the optical length of both axial rays alike, so that matched eye pieces can be used and the necessity of using. the auxiliary eyepiece of longer focus than that in the main tube is rendered unneces- 2w sary. I

For convenience I have termed eyepoints those points at which are formed the Ramsden circles or eyepiece images of the upper focal plane of the objective.

When the separation of the eyepieces is such that the separation of the two axial rays at the plane of the eye points correspond to the pupillary distance of the observer, the twoimages appear identical in every respect and 8 the only advantage that binocular vision possesses under these conditions is that it reduces the tendency to fatigue by dividing the work between the two eyes, If, however, the adjustment is such as to bring the axial rays alittle closer together than the pupillary distance of the observer, a. stereoscopic condia, tion results owing to the inability of one or both eyes under these conditions to receive: those pencils of rays which come from the re- 5 spective sides of the back of the objective, and similarly a greater separation of the" axial rays results in a pseudoscopic condition.

In practice it is sufficient to adjust for binocular non-stereoscopic vision with the eyes held at the plane ofthe eye-points since owing to parallax of axes approaching the eyes to the lenses brings the axial rays within the pupillary distance and withdrawing them above the plane of the eye-points brings the axial rays. without the papillary distance. This is so far true that with low-power eyepieces and objectives all three kinds of vision may befobtained by alterations in the position of the eyes, which are not sufficient to contract the field of vision and uniform illumi nation.

It is preferable to mount the compound prisms 6 7 within a slide 20, which can be instantly removed, so as to convert the instrument into an ordinary draw-tube monocular microscope with place for inserting a vertical illuminator or other .tube accessories.

A special feature of my invention is the construction of the compound prism with metallic reflecting-surface permanently sealed up within it. Similar results have heretofore been obtained only by means of unsilvered prisms having juxtaposed reflectingsurfaces necessarily at a flatter angle to avoid total reflection, thereby objectionabl y increasing the length of the reflected ray and necessitating extremely accurate work in the polishing of the reflecting-surfaces and in their approximation in such manner as to make the two reflections practicallycoincident. Anotherobjection to such unsealed compound prisms is the fact that the inclosed surfaces sometimes become so misty as to seriously effect their performance, and the prisms cannot be separated, cleaned, and properly reseated and adjusted except byan expert. They are also incapable of securing approximately equal division of the illumination between the two images, one being always more brilliantly lighted than the other, and owing to the greater length of the reflected ray they do not so readily permit of adaptation to the short-tube construction for which the great majority of microscopic objectives are now adjusted by manufacturers. Inasmuch as the compound prism with transparent silvering is equally efficient at any available point between the objective and the eyepieces some of the merits of my invention may be realized in the form of a binocular eyepiece, such as shown.

in Fig. 2, in which 21 represents a box or casing applied to the upper end of the tube 9 and having a compound prism 6 7 and an adj ustable reflecting-prism 8, this box or casing having two projecting eyepieces 12 and 18,

the latter being mounted so as to swing upon.

the same axis as the adjustable prism 8 The meeting surfaces of the prisms 6 7 are provided with a transparent silvered or platinized reflector, and said prism 6* has two other reflecting-surfaces 6 and 6 be- ,cause'of the disposition of the eyepiece 12* laterally out of line with the main tube 9. This construction possesses the disadvantage that it increases the optical tube length of'the microscope, thereby reducing its eificiency withhigh-power objectives which have been corrected to perform most perfectly with theshortest tubes; but it might be preferred for'use with long-focus objectives on microf he naneyepiece, s I 0 scopes having limited range of focus between" ,7

stageand objective scre While I prefer the compound prism with? permits of obtaining stereoscopic vision with a compound prism having opaque silvering over half of the inclosed area with perfect transparency of the other half, as shown in Fig. 3. The performance of this combination does not difler materially from that of a Wenham binocular; but it possesses the advantages that it may be adapted to any ordinary monocular microscope and used with the short or continental length of tube.

When it is not desired to effect independent adjustment of the supplementary eyepiece and adjustable reflecting-prism, simultaneous adjustment of the same may be effected-as, for instance, by a device of the character shown in Fig. 4, in which the screw 22, which effects adjustment of the reflectingprism, has two threaded portions, one engaging with a threaded portion of the box or casing 5 and the other with a threaded projection upon a swinging arm or frame 23, which carries the supplementary eyepiece. This arrangement provides for the necessary differential movement of the prism and eyepiece.

Myinvention permits parallax vision,which 1 1. The combination in a binocular micro scope, of a pair of separated eyepieces, a compound prism consisting of two cemented prisms, the inclosed face of one of which car ries a metallic reflecting-surface, and means whereby the rays divided by said compound prism are directed to the separated eyepieces, substantially as specified.

2. The combination in a binocular microscope, of a pair of separated eyepieces, a compound prism consisting of two cemented prisms, the inclosed face of one of which car ries a transparent metallic reflecting-surface, and means whereby the rays divided by said compound prism are directed to the separated eyepieces, substantially as specified.

3. The combination in azbinocular microscope, of a compound prism having a transparent metallic reflectingesurface and an adjustable reflector receiving the rays reflected from said surface, substantially as specified.

4.. The combination in a binocular micro scope, of a main eyepiece, a'compound prism having a transparent metallic reflecting-surface, an adjustable reflector receiving the rays reflected from said surface, and a supplementary eyepiece matching the main eyepiece and receiving the rays reflected from the adjustable reflector, id-su e eiece. o ustable 'froman lementa owar, j antia yass ed.

5. A binocular microscope having a reflecting-prism whose body is extended in the direction of its emergent ray for the purpose f altering the position of the focal plane of a reflected image, substantially as specified,

6. The combination in a binocular microscope, of acompound prism with transparent metallic reflecting-surface and an adjustable reflecting-prism having an extension of its body in the direction of its emergent ray, substantially as specified. I

7. The combination in a binocular microscope, of the main tube of the microscope having a projecting plate or bar mounted upon the eyepiece end of the same, a supplementary eyepiece, a carrier therefor, and means for adjustably securing said carrier to the projecting plate or bar of the main tube, substantially as specified.

8. The combination of the main tube of a microscope, with an attachment for binocular vision, said attachment comprising an auxiliary eyepiece at the upper end of the tube, and a prism combination at the lower end of the same, with uninolosed space between the two, substantially as specified.

9. The combination in a binocular microscope, of a pair of separated eyepieces, a comound prism consisting of two cemented prisms incloslng a limited area of metallic reflecting-surface, and means whereby the rays combination with a reflecting-prism which receives the reflected rays from said compound prism, substantially as specified.

11. The combination of a binocular microscope prism consisting of two cemented prisms having an inclosed metallic reflectingsurface and adjustable prism receiving the rays reflected from said compound prism and having an extension of its body in the direction of its emergent ray, substantially as specified.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

FREDERIC E. IVES.

\Vitnesses:

F. E. BECHTOLD, J 0s. H. KLEIN. 

